The present invention relates to a method for processing a database, a system for processing a database, and a medium relevant thereto, and more particularly to a processing method for passing data in a database system configured in a client-server manner.
Concerning a method for managing in a database a massive amount of batch data ranging to several giga bytes such as moving picture data, video data and audio data, there has been proposed a method having a BLOB (Binary Large Object) system proposed by the SQL3 (“Database Language SQL”, ISO Working Draft, July 1996). When an application program treats the BLOB data, the application program uses a variable consisting of four bytes called as a locator for uniquely identifying the BLOB data and creates the variable as the BLOB data when the value is evaluated.
For example, when a database system treats a massive amount of data, it is disadvantageously necessary to secure a large memory area for a program on which a user application is running. In order to overcome this disadvantage, as a method for treating the BLOB data by holding the BLOB data in a file without using a memory buffer for holding the massive amount of data in the application program, a file reference technique of the database managing system DB2 (“USING THE NEW DB2 IBM's Object-Relational Database System”, Don Chamberlin, Morgan Kaufmann Publishers, Inc., 1996) may be used.
On the other hand, a relational database may employ a parallel database that enables to process a massive amount of data at fast speed. The parallel database may employ a function of selecting the most approximate parallel processing according to the content of query and the state of data in the parallel database (the function of which is disclosed in JP-A-6-214843).
Further, the object relational database (“OBJECT RELATIONAL DBMSs”, Michael Stonebraker, translated by K. OHTA, International Thomas Publishing Japan, August 1996) has a technique of implementing a routine function of SQL3 by using the executable codes created by describing a routine function of SQL3 in a general-purpose programming language and manipulating multimedia data such as pictures through the use of the SQL using the routine.
As a method for sharing data between processes, a technique of a memory mapped file in an operating system UNIX and so forth may be referred (X/Open Portability Guide, XPG4V2).